This is a good example, of why bullet matters, and load matters so much.
This is using 16" Proof Research Barrel, AR15. These are typically 7 shot groups, but some are more than that..like the 24 grain M855.
The M855 are not pulled, they are new production, STEEL CORE 62, grain bullets.
THe 60 Grain V-MAX are widely known and used.
M855 Steel Core bullets are not known for accuracy. They have a mild steel insert in them, and if its not "perfectly" centered, which it isn't, accuracy suffers. the question is...this..consider this...
"If Military M4's and M16's are typically 2-4 MOA rifles using standard Military Ammo, and my Civilian AR15 shoots Steel Core 62 grain at basically ~3 MOA...DOES IT MATTER?"
No, it doesn't matter, its good enough.
But every so often, we find a magic load. Could this be it?
24.5 Grains of Benchmark using 60 grain V-MAX at 2.250 OAL, using Federal Match primers and new brass? Even the 25.0 groups are decent. Not as good as the 2, 24.5..but hey...its good enough.
This Proof Research Carbon Fiber barrel is not even close to as accurate as the WOA or Shilen WOA barrels I have, but its a little under 1 MOA using the good loads....sub MOA and very lightweight and extremely dirable. I really like it.
Very good barrel. Just not great value.